Mus: Fixes rendering of transparent containers.

services/ui/ws/frame_generator.cc

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "services/ui/ws/frame_generator.h"
 
 #include "cc/output/compositor_frame.h"
 #include "cc/quads/render_pass.h"
 #include "cc/quads/shared_quad_state.h"
 #include "cc/quads/surface_draw_quad.h"
@@ skipping 101 matching lines @@
   if (!window->visible())
     return;
 
   ServerWindowSurface* default_surface =
       window->surface_manager() ? window->surface_manager()->GetDefaultSurface()
                                 : nullptr;
 
   const gfx::Rect absolute_bounds =
       window->bounds() + parent_to_root_origin_offset;
   std::vector<ServerWindow*> children(window->GetChildren());
-  // TODO(rjkroege, fsamuel): Make sure we're handling alpha correctly.
   const float combined_opacity = opacity * window->opacity();
   for (auto it = children.rbegin(); it != children.rend(); ++it) {
     DrawWindowTree(pass, *it, absolute_bounds.OffsetFromOrigin(),
                    combined_opacity);
   }
 
   if (!window->surface_manager() || !window->surface_manager()->ShouldDraw())
     return;
 
   ServerWindowSurface* underlay_surface =
       window->surface_manager()->GetUnderlaySurface();
   if (!default_surface && !underlay_surface)
     return;
 
   if (default_surface) {
     gfx::Transform quad_to_target_transform;
     quad_to_target_transform.Translate(absolute_bounds.x(),
                                        absolute_bounds.y());
 
     cc::SharedQuadState* sqs = pass->CreateAndAppendSharedQuadState();
 
     const gfx::Rect bounds_at_origin(window->bounds().size());
     // TODO(fsamuel): These clipping and visible rects are incorrect. They need
     // to be populated from CompositorFrame structs.
     sqs->SetAll(quad_to_target_transform,
                 bounds_at_origin.size() /* layer_bounds */,
                 bounds_at_origin /* visible_layer_bounds */,
                 bounds_at_origin /* clip_rect */, false /* is_clipped */,
-                window->opacity(), SkXfermode::kSrcOver_Mode,
+                combined_opacity, SkXfermode::kSrcOver_Mode,
                 0 /* sorting-context_id */);
     auto quad = pass->CreateAndAppendDrawQuad<cc::SurfaceDrawQuad>();
     quad->SetAll(sqs, bounds_at_origin /* rect */,
                  gfx::Rect() /* opaque_rect */,
                  bounds_at_origin /* visible_rect */, true /* needs_blending*/,
                  default_surface->id());
   }
   if (underlay_surface) {
     const gfx::Rect underlay_absolute_bounds =
         absolute_bounds - window->underlay_offset();
     gfx::Transform quad_to_target_transform;
     quad_to_target_transform.Translate(underlay_absolute_bounds.x(),
                                        underlay_absolute_bounds.y());
     cc::SharedQuadState* sqs = pass->CreateAndAppendSharedQuadState();
     const gfx::Rect bounds_at_origin(
         underlay_surface->last_submitted_frame_size());
     sqs->SetAll(quad_to_target_transform,
                 bounds_at_origin.size() /* layer_bounds */,
                 bounds_at_origin /* visible_layer_bounds */,
                 bounds_at_origin /* clip_rect */, false /* is_clipped */,
-                window->opacity(), SkXfermode::kSrcOver_Mode,
+                combined_opacity, SkXfermode::kSrcOver_Mode,
                 0 /* sorting-context_id */);
 
     auto quad = pass->CreateAndAppendDrawQuad<cc::SurfaceDrawQuad>();
     quad->SetAll(sqs, bounds_at_origin /* rect */,
                  gfx::Rect() /* opaque_rect */,
                  bounds_at_origin /* visible_rect */, true /* needs_blending*/,
                  underlay_surface->id());
   }
 }
 
 }  // namespace ws
 
 }  // namespace ui